Machine tool with a mechanical cutting tool changer



Oct. 27, 1964 J. A. HANSEN ETAL Re. 25,670

MACHINE TOOL WITH A MECHANICAL CUTTING TOOL CHANGER 5 Sheets-Sheet 1Original Filed March 10, 1958 INVENTORS 6 u w "r w 5 "A W HD 4&4 n y MawJVCK. v:

oct. 27, 1964 HANSEN ETAL Re. 25,670

MACHINE TOOL WITH A MECHANICAL CUTTING TOOL CHANGER 5 Sheets-Sheet 3Original Filed March 10, 1958 S C R i m n w -31 m 6 w m? m fls m &4 n Axy Jam Y B Oct. 27, 1964 J HANSEN ETAL Re. 25,670

MACHINE TOOL WITH A MECHANICAL CUTTING TOOL CHANGER Original Filed March10, 1958 5 SheetsSheet 4 Af/arn@y Oct. 27, 1964 J. A. HANSEN ETAL 25,570

MACHINE TOOL. WITH A MECHANICAL CUTTING TOOL CHANGER Original FiledMarch 10, 1958 5 Sheets-Sheet 5 4 75 J?! a 480 A/ 15 7)? I 482 9/ 1 I r#98 I 496 I 4K9? 4,40 g] I I 472 -INVENTORS Joim A Hansen BY Char/es A,Pars/re Karl Afifaoci A forngy United States Patent 25,670 MACHINE TOOLWITH A MECHANICAL CUTTING TOOL CHANGER John A. Hansen, Granhy, Conn.,and Charles A. Parske and Kurt A. Riedel, Milwaukee, Wis., assignors toKearney & Trecker Corporation, West Allis, Wis., a corporation ofWisconsin Original No. 2,952,170, dated Sept. 13, 1960, Ser. No.720,395, Mar. 10, 1958. Application for reissue Sept. 13, 1962, Ser. No.223,569

18 Claims. (Cl. 77-25) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates generally to machine tools and more particularlyto an improved machine tool especially adapted to rapidly effect achange of rotary cutting tools to enable the machine to perform severaldifferent machining operations on one or more workpieces in rapidsuccession.

It is a general object of the present invention to provide an improvedmachine tool incorporating a mechanical cutting tool changer.

Another object of the present invention is to provide a machine toolwith a cut-ting tool changer especially adapted to present differenttypes of rotary cutting tools for utilization by the machine with amechanism for automatically connecting the selected cutting tool to adrive mechanism for rotating the cutting tool.

Another object is to provide an improved machine tool with a cuttingtool changer adapted to make available a substantial quantity ofdifferent cutting tools for operation with the machine to enable themachine to rapidly perform .a succession of different machiningoperations.

Another object is to provide an improved machine tool employing a rotarycutter and incorporating l2. tool changer that functions to change thecutting tool in the machine with rapidity while requiring a minimum ofetfort on the part of the operator.

Another object is to provide a machine tool which has a variety ofrotary cutting tools immediately available and automatically positionsand connects a selected one of the cutting tools for rotation by thepower drive of the machine and operates to position and feed theselected rotating cutting tool toward a workpiece for performing amachining operation while maintaining the driving connection.

Another object is to provide a machine tool with a mechanical toolchanger having a number of cutting tools available for selectiveoperation with the machine, the machine being operable to position theselected tool in three mutually transverse paths relative to aworkpiece.

A further object is to provide a machine tool having a mechanicalcutting tool changer, the machine being capable of automatic operationand incorporating suitable hydraulic and electrical interlocks thatserve to control its operation in the event of a malfunctioning of aportion of the mechanism for the purpose of preventing damage to themachine, the cutter or the workpiece.

According to this invention the improved machine tool comprises a baserotatably supporting a drum, the drum being also rectilinearly movableon the base in two mutually transverse paths. A plurality of bores areformed in the drum with the axes of the bores being parallel to the axisof the drum and equally spaced along a circle adjacent to the peripheryof the drum. Each of the bores contains a tool carrying spindle that isrotatably mounted in a quill which is slidably carried within the borefor the purpose of rendering the spindle axially adjustable. A cuttingtool is attached to the forward end of each of the Re. 25,671 ReissuedOct. 27, 1964 spindles while a clutch element is secured to the opprsite end. The drum is indexable to bring any one of th spindles and itsassociated cutting tool into operating pos tion and when so located, theclutch element carried b the spindle will be in alignment with acooperating clutc element connected to be driven by a variable speetransmission.

The transmission is mounted on a slide that is movabl carried by themachine so that movement of the slide wi produce a like movement of thetransmission. The slid is provided with coupling means for coupling thequill of a spindle that has been brought into operating positio to theslide in order that movement of the latter ma operate to adjust thespindle axially in a positioning an feeding movement. The coupling meansis arranged s that initial movement of the slide is relative to thespindl for the purpose of moving the transmission and its assc ciatedclutch element to move the transmission clutc element into engagementwith the spindle clutch elemer for completing a driving connection fromthe transmis sion to the tool carrying spindle. After the clutch elements are engaged, the coupling means operates to connec the spindle formovement with the slide and movemer of the slide will then function toposition and feed th spindle and its associated cutting tool relative toa work piece. Upon completion of a machining operation, th spindle maybe retracted and the drum may then b indexed to bring a new cutting toolinto operating position The foregoing and other objects of thisinvention, whicl will become more fully apparent from the following detailed description, may be achieved by means of the ex emplifyingapparatus depicted in and set forth in thi specification in connectionwith the accompanying draw ings, in which:

FIGURE 1 is a perspective view of a machine tool in corporating thefeatures of the present invention;

FIG. 2 is an enlarged fragmentary View partly in verti cai section andpartly in side elevation illustrating thi arrangement of the drum andthe spindle positioning EIIK feed slides when in their forward position;

FIG. 3 is an enlarged fragmentary view partly in vertical section andpartly in side elevation depicting a drilling and counterboring spindlein its retracted position along with the positioning and feed slides intheir fully retracted position;

FIG. 4 is a detail view partly in vertical section anc' partly in sideelevation showing a tapping spindle that is carried in one of the boresof the drum illustrated ir FIG. 1;

FIG. 5 is a detail view substantially in rear elevatior illustrating theroller track for retaining the inoperative spindles in their retractedposition within the drum;

FIG. 6 is a rear elevational View of the roller track, similar to FIG.5, but also depicting the opening in the back plate of the track forremoving the spindle and their associated quills from the drum;

FIG. 7 is a detail view substantially in side elevation illustrating themechanism for coupling and operatively locking the located spindle tothe positioning and feed slides;

FIG. 8 is a diagrammatic View of the hydraulic circuit incorporated inthe machine; and,

FIG. 9 is a diagrammatical showing of the electrical control circuit forcontrolling the operation of the machine.

Reference is now made more particularly to the drawlugs and specificallyto FIG. 1 thereof illustrating a machine tool incorporating the variousfeatures of the present invention. As there shown, the machine generallycomprises a base 10 which presents a pair of horizontal ways 11longitudinally disposed along its upper 6! face. The ways 11 are engagedby complementary vs (not shown) formed on the underside of a carriage.erally identified by the reference numeral 12, the vs 11 functioning toslidably support the carriage 12 movement along the bed 10. The carriage12 com- ;es a horizontal base 13 which is provided with the ys (notshown) along its underside for engagement h the ways 11. The base 13supports an upstanding umn 14 and an overhanging cap 15 formed on theJ61 end of the column 14. the interior face of the column 14 is providedwith air of vertical ways 19 that slidably support a saddle for verticalmovement. The Vertical movement of saddle 20 is etfected by means of ascrew 21 that ournalled at one end in the cap 15 and at its opposite Iin the base 13. The screw 21 is in threaded en- ;ement with acooperating nut (not shown) which is :nred to the saddle 20. Rotation ofthe screw 21 will refore cause a movement of the saddle 20 along the ys19 in either direction, depending upon the direcn of rotation of thescrew 21, and the screw may be :ated by any suitable means, as forexample, the irce of power 22 located on top of a cap 15 above screw 21.The saddle 20 is therefore movable either rtically or horizontallyrelative to the bed 10. The lower portion of the saddle 20 is disposeddirectly ave the carriage 13 and extends upwardly therefrom rotatablysupport the drum 25. The drum 25 funcn to carry a plurality of cuttingtools and their asso- Lted spindles for selective operation with themachine. this end, the drum 25 is provided with a plurality bores 26which serve to rotatably and slidably suprt the spindles in a manner tobe subsequently defibed. The bores 26 extend through the entire depththe drum 25 and are equally spaced along a circle jacent to theperiphery of the drum with their axes ing parallel to the axis of thedrum. A circular shroud is disposed about the rearward portion of thedrum protect the operating mechanism. The forward portion of the bed 10presents an elevated rface for supporting a pair of inverted V-shapedways i that extend longitudinally thereof for slidably carryg a pallet31 upon which a workpiece (not shown) 1y be secured in position to beoperated upon by one the cutting tools carried by the drum 25. TheV-shaped ways 3% are interrupted by a rotary table 1 which presents apair of V-shaped ways 33 on its upper rface which conform to the ways 30in spacing and lnfiguration so that they may be aligned therewith to irmcontinuous ways upon which the pallet 31 may be oved. When the pallet 31is first moved into operatg position, the ways 33 of the rotary table 32will be alignment with the ways 3t) of the bed 19. The palt 31 istherefore slid along the ways 39 onto the ays 33 and is secured bysuitable means (not shown) the rotary table 32. If necessary, the rotarytable may then be revolved and indexed to effect a like ltary movementof the workpiece that is secured to .e pallet 31 so that a machiningoperation may be perrmed on one or several sides of the workpiece.

It is to be understood that a conventional machine |ol table may besubstituted for the pallet and way 'rangement illustrated in theexemplary embodiment. lowever, the pallet and way construction isdepicted in rder to disclose a machine which is capable of comletelyautomatic operation in which the pal'ets 31 with 'orkpieces securedthereto are moved successively by conveyor onto the ways 30 and 33 witheach of the allets 31 being secured successively to the rotary table 2.The workpiece on the pallet 31 will then be located t the operatingstation and may then be operated upon y one or more of the cutting toolscarried by the rum 25 to complete the desired machining operation riththe cutting tools that are employed being located uccessively at theoperating station by rotating the drum to its appropriate indexpositionv Such operation of the machine may be performed under thecontrol of recorded information, as for example, the signals receivedfrom a punched or magnetic tape.

The manual controls are conveniently supported at the front of themachine on a control panel 38 that is mounted on the exterior end of ahorizontal arm 39. The latter, in turn, is pivotally carried by anupstanding post 44] that is secured to the front of the bed 10.

The mounting of the drum 25 on the saddle 20 is clearly shown in FIG. 2,the saddle presenting a forwardly and horizontally extending post 45that protrudes into a bore 46 concentrically formed in the drum 25. Theforward end of the bore 46 is sealed by a closure 47 which is attachedto the drum 25 to rotate with it. The interior surface of the closure .7is provided with a concentric circular recess for receiving a rollerbearing 48 in which the post 45 is journalled. The interior end of thedrum 25 is rotatably supported by a roller bearing 49 that has its innerrace mounted on the post 45 and its outer race in engagement with thebody of a spur gear 50. The spur gear 59 is secured to the interior endof the drum 25 by suitable cap screws 51 which extend through the gearinto threaded engagement with an annular flange that extends inwardlyinto the bore 46. The drum 25 is therefore rotatably supported by thetwobearings 48 and 49 that serve to render it freely rotatable upon thepost 45 which is secured to the saddle 20.

Rotation of the drum 25 may be achieved by revolving a spur gear 55which is in meshing engagement with a cooperating spur gear 56. The spurgear 56 is keyed to a shaft 57 that is rotatably supported by the saddle20 and has another gear 58 keyed to its opposite end in position to meshwith the gear 56. The gear 55 is keyed to a shaft 5% that is rotatablysupported by the saddle 2t) and is connected to suitable mechanism (notshown) to produce the indexing movement of the drum 25 in well knownmanner. Rotation of the shaft 59 will produce the desired rotation ofthe drum 25.

If the drum 25 is to be indexed manually, a simple hand crank may beattached to the shaft 59 for manual operation and a detent mechanism(not shown) may be provided to establish the indexing positions of thedrum to establish the operating location for each of the bores 26. Theoperator may then rotate the hand crank to revolve the drum 25 until thedetent mechanism is engaged at the desired index position to place theselected bore 26 at the operating station. On the other hand, the shaft59 may be connected to a source of power for power operation of the drum25 and the source of power may be regulated by a control mechanism forautomatically effecting the desired indexing movement, as for example,in the manner disclosed in the copending patent application of John A.Hansen, Serial No. 720,- 361, filed March 10, 1958.

In order to provide for automatic operation of the indexing movement ofthe drum 25, an indicator shaft 63 extends through a bore 64- formed inthe post 45 and is rotatably journalled within the post for rotationrelative thereto. The shaft 63 is provided with a splined end 65 at itsforward extremity to engage a complementary splined hole formed in theclosure 47. The splined connection with the closure 47 serves to causethe indicator shaft as to rotate with the drum 25 relative to the post45 so that the shaft 63 may be connected to indicate the amount ofrotation in any well known manher to accommodate either manual orautomatic indexing of the drum 25. Thus, for example, if the drum 25 isto be indexed automatically, the shaft 63 may be connected so that itsrotation with the drum 25 will serve to produce electrical impulses thatwill indicate the degree of rotation of the drum Z5 and cooperate with acontrol circuit to regulate the operation of the source of power so thatthe desired indexing of the drum 25 is obtained.

Since the apparatus for producing such automatic indexing of the drum 25is not a part of the present invention, it is not here described orshown and the features of the present invention will operate with anytype of indexing mechanism even though it may be a simple manualrotation of the shaft 59.

The drum 25 may be locked in the selected index position by means of ahydraulically actuated locking plunger 70 that is slidably carried bythe saddle 20 for selective insertion into any one of a plurality ofholes 71 formed in the rear Wall of the drum 25. The number of holes 71corresponds to the number of bores 26 in the drum with each of the holes71 being located for receiving the plunger 70 when the drum 25 has beenindexed to locate one of the spindles in the bores 26 at the operatingstation.

One end of the plunger 70 is provided with a piston 72 slidably disposedwithin a cylinder 73 that is formed in the saddle 20. A pair of conduits74 and 75 serve to carry hydraulic pressure to and from the cylinder 73for the purpose of actuating the piston 72 and its associated plunger70. When it is desired to move the plunger 70 into one of the holes 71for locking the drum 25 in position, hydraulic pressure is admitted intothe right end of the cylinder 73 as viewed in FIG. 2, through theconduit 75 and the exhaust fluid is carried from the left side of thepiston 72 through the conduit 74. The plunger 70, of course, iswithdrawn from the hole 71 by admitting fluid pressure to the left endof the cylinder 73 through the conduit 74 and the exhaust fluid is thencarried from the cylinder 73 by the conduit 75.

In the event the drum 25 is arranged to be indexed manually by manualrotation of the shaft 59, the holes 71 in the drum 25 may also serve tocooperate with a detent mechanism for accurately locating the drum 25 inthe indexed positions. Thus, a spring urged ball (not shown) may becarried by the saddle 20 in position to partially enter the holes 71 asthe drum 25 rotates, and as the ball is urged by the spring into any oneof the holes 71, the ball will yieldably retain the drum 25 in thatparticular position to properly locate it for placing one of thespindles at the operating station. Additional torque on the shaft 59will overcome the spring pressure upon the ball to permit furtherrotation of the drum 25 to the succeeding index position, and actuallocking of the drum 25 in the desired position is achieved by actuatingthe plunger 70 as described to enter one of the holes 71.

The machine illustrated as an exemplary embodiment is arranged toperform drilling, counterboring and tapping operations although it is tobe understood that other types of cutting tools may be employed with thestructure of the present invention without departing from its spirit andscope. The spindle arrangement illustrated in FIGS. 2 and 3 is providedto perform both drilling and counterboring operations while the spindledepicted in FIG. 4 is utilized for performing tapping operations.

The drilling and counterboring arrangement comprises a spindle 80rotatably supported within an inner quill 81 by two ball bearings 82.The inner quill 81 is slidably supported for axial movement within anouter quill 83 which, in turn, is likewise slidably supported for axialmovement Within one of the bores 26 of the drum 25. A key 84 is securedto the outer quill 83 by means of screws 85 and is disposed Within acooperating slot 86 to prevent the outer quill 83 from rotating withinthe bore 26 without interfering with its axial movement. As clearlyshown in FIG. 1, a slot 86 is provided for each of the bores 26 andextends radially from the bore 26 to the periphery of the drum 25. Theforward end of the spindle 80 is provided with a suitable chuck 87 forremovably securing a cutting tool 88 therein in well known manner. Sincethe cutting tool 88 is illustrated as being a drill of considerablelength in FIGS. 2 and 3, a guide or drill bushing 89 is provided forguiding the drill 88 in its feeding movement, the guide 89 being se- 6cured by a screw 90 to the exterior end of the outer quill 83.

Power for individually driving the several spindles carried by the drum25 is derived from a hydraulic motor that is connected to drive avariable speed transmission generally identified by the referencenumeral 96. The motor 95 is mounted on a transmission housing 97 whichis supported on top of a feed slide 98 so that the transmission 96 willmove With the feed slide. The transmission 96 operates to drive anoutput shaft 99 which is journalled in the transmission housing 97 andfunctions to drive any one of the spindles that may be selected with thedriving connection being made through a clutch generally identified bythe reference numeral 101.

The clutch 101 comprises two clutch elements 102 and 103 with the clutchelement 103 being secured to the end of the output shaft 99 while aclutch element 102 is attached to the interior end of each of thespindles that are carried Within the several bores 26. Each of thespindles may therefore be connected by the clutch 101 to be rotated bypower from the motor 95 and the driving connection may be broken bydisengaging the clutch 101 to permit the drum 25 to be indexed forbringing a new spindle to the operating station.

The rate of operation of the motor 95 may be varied by adjustment of ahydraulic flow control valve which is a part of the hydraulic circuit tobe subsequently described and which may be adjusted to infinitely varythe rate of operation of the hydraulic motor 95 within prescribedlimits. The transmission 96 shown as an exemplary embodiment is a threestep transmission, shiftable into three positions to furnish three speedranges for operation in conjunction with the infinitely variable speedfeature of the hydraulic motor 95 so that the spindles may be rotated atinfinitely variable rates within a wide range as established by thefixed step transmission operating in conjunction with the infinitelyvariable rate of operation of the hydraulic motor 95. The particularpower train illustrated is a preferred embodiment but it is to beunderstood that other types of power trains may be provided withoutdetracting from the performance of the features of the presentinvention.

Shifting of the transmission 96 is effected by the movement of a piston108 located within a cylinder 109 formed in the transmission housing 97.The piston 108 is provided with a gear rack 110 disposed to mesh with agear segment formed on the upper edge of a pivotable shifting fork 111.The shifting fork 111 may pivot about a pin 112 and engages a gearcluster 113 which has splined engagement with the output shaft 99 sothat the gear cluster 113 may be shifted into three operating positionsalong the shaft 99 without interrupting its driving connection with theshaft to establish the three speed ranges of the transmission. The gearcluster 113 includes three gears that are adapted to be selectivelyengaged with three complementary gears keyed to a drive shaft 114. Thedrive shaft 114 is connected to be driven by the hydraulic motor 95 sothat the power from the motor 95 is transmitted through the shaft 114 tothe output shaft 99 through the cooperating gears for driving theselected spindle.

Shifting of the gear cluster 113 is effected by actuating the piston 108into any one of three positions to cause a pivotable movement of theshifting fork 111. If hydraulic pressure is admitted into the right endof the cylinder 109 through a conduit 115 the piston 108 will be movedto the left end of the cylinder 109 to cause a pivoting of the shiftingfork 111 for shifting the gear cluster 113 to its extreme rightwardposition along the splined portion of the output shaft 99 to establishthe high speed range of operation. On the other hand, if hydraulicpressure is admitted to the left end of the cylinder 109 through aconduit 116, the piston 108 will be moved to the right end of thecylinder 109 to pivot the ihifting fork 111 in a direction for movingthe gear cluster [13 to its extreme leftward position to establish thenedium speed range of operation. The low speed range )f operation isachieved by admitting pressure to both :onduits 115 and 116 to centerthe piston 198 within the :ylinder 109 in the manner illustrated in FIG.3. In this nanner, three ranges of operation are provided for op-:rating in conjunction with the infinitely variable rate of operation ofthe hydraulic motor 95 to provide an infinitely variable nate ofrotation of the spindles through a wide range.

The piston 108 is a pressure differential piston to insure that it willbe accurately centered when pressure is admitted to both ends of thecylinder 1119. To this end, it is provided with reduced end portions 120and 121 for slidably receiving sleeves 122 and 123 respectively whichoperate in well known manner to cause the piston 168 to center itselfwhenever reasonably equal pressures are admitted into both ends of thecylinder 109.

The upper portion of the piston 108 is provided with a central notch 132in its upper surface for receiving the plunger of any one of three limitswitches 134, 135 and 136 depending upon the position of the piston 108.When the piston 168 is shifted to one of its three positions, the notch132 will be located to receive the plunger of one of the three limitswitches. As the plunger of the limit switch enters the notch 132 itactuates its associated switch to indicate that the desired speed rangeis established. Thus, when the piston 198 is moved to its extremerightward position, the plunger of the limit switch 134 will drop intothe notch 132 to indicate that the medium speed range has beenestablished in the transmission 96. In like manner, the limit switch 135indicates that the high speed range is established while the limitswitch 136 indicates that the low speed range has been established whenits plunger enters the notch 132 as illustrated in FIG. 3.

The feed slide 98 and a positioning slide 142 are slidably carried bythe saddle 20, being mounted on ways 143 that are formed on the portionof the saddle 29 that lies beneath the drum 25. The ways 143 cooperatewith complementary ways formed on the underside of the feed slide 93 andthe positioning slide 142 to slidably support the slides for horizontalcross positioning movement toward and away from the drum 25. The feedslide 98 and the positioning slide 142 will move together except wheneffecting a feeding movement in a drilling operation, at which time thefeed slide 98 will move relative to the positioning slide to feed thedrill into the workpiece.

Power for producing the combined movement of the feed and positioningslides is derived from a hydraulic motor 147 which is connected to drivea screw 148 through a pair of cooperating spur gears 149 that arerotatably supported within a recess formed in a back plate 159 whichextends upwardly from the rear portion of the saddle 20 as clearly shownin FIG. 3. The motor 147 is mounted on the back plate 150 and isconnected to drive the gears 149. The screw 148 is journalled in theback plate 150 and extends forwardly therefrom into threaded engagementwith a split nut 151 that is fixedly secured to the positioning slide142 within a bore 152. A cooperating bore 153 is also formed in the feedslide 98 for the purpose of providing clearance for the forward end ofthe screw 148. The nut 151 is of split construction so that it may beadjusted for eliminating back-lash between the screw and the nut in wellknown manner.

Since the nut 151 is fixed to the positioning slide 142, rotation of thescrew 148 will cause a movement of the slide 142 along the ways 143. Thefeed slide 98 is coupled to the positioning slide 142 to move with it bya piston 158 and its associated connecting rod 159. The piston 153 isdisposed within a cylinder 160 formed in the positioning slide 142 andits connecting rod 159 ex tends forwardly through a suitable bore formedin the positioning slide 142 to be attached to the feed slide 98 bymeans of a pin 161.

Hydraulic pressure is admitted to the cylinder 160 through a pair ofconduits 162 and 163 with the conduit 162 being in communication withthe left end of the cylinder 160 while the conduit 163 is incommunication with the right end of the cylinder 160 as clearly shown inFIG. 3. During operation of the machine, hydraulic pressure iscontinuously directed into the conduit 162 to admit pressure into theleft end of the cylinder 160 as viewed in FIG. 3 for forcing the piston158 to the right end of the cylinder and thereby couple the feed slide98 to the positioning slide 142 so that the two slides will move inunison when the hydraulic motor 147 is actuated. It is only during adrill feeding movement that the How of hydraulic pressure in theconduits 162 and 163 is reversed so that the pressure is directed intothe conduit 163 to admit it into the right end of the cylinder 166 forforcing the piston 158 to the left end of the cylinder and thereby movethe slide 98 leftwardly relative to the positioning slide 142. Uponcompletion of the feeding movement, the flow of hydraulic pressure intothe cylinder 160 is again reversed and maintained to securely couple thetwo slides together.

The unitary cross positioning movement of the feed slide 98 and thepositioning slide 142 is controlled by a plurality of limit switchesmounted on the saddle 20 to be actuated by a dog 167 that is attached tothe positioning slide 142 to move with it. A cross positioning reverselimit switch 168 presents an upwardly extending spring urged plunger 169which is forced downwardly by the dog 167 when the slides 98 and 142arrive at their fully retracted position to actuate the limit switch 168for terminating the operation of the motor 147 in a manner to besubsequently described. Another limit switch 170 is likewise actuated bythe dog 167 for an interval during the final portion of the rearwardmovement as well as during the initial portion of the forward movementof the slides, and serves to control the flow of hydraulic pressure tothe motor 147 so that the rate of operation of the motor is maintainedat a creep speed during the interval when the limit switch 170 isactuated by the dog 167. Forward unitary movement of the slides 98 and142 is limited by a forward limit switch 171 which is actuated by thedog 167 when the slides arrive at their combined forwardmost position toterminate operation of the motor 147 and thereby stop the forwardmovement of the slides.

The movement of the slides 98 and 142 serves to engage the clutchelement 103 with the clutch element 102 of the selected spindle tocomplete the driving connection from the hydraulic motor 95 for rotatingthe spindle, and the movement of the slides 98 and 142 further functionsto position the selected spindle for performing a machining operation.The simultaneous movement of the slides 98 and 142 by operation of themotor 147 also serves to feed the operating spindle for a counterboringoperation, and as previously mentioned, the additional movement of thefeed slide 98 relative to the positioning slide 142 serves to feed aselected spindle 80 in a drilling operation. In order to perform thesefunctions, it is necessary for the slides to be coupled to the quills 81and 83, and to this end a pair of rods or bars 179 and 180 are slidablysupported within suitable bores formed in the feed slide 98 beneath thetransmission housing 97 as best shown in FIGS. 3 and 7. The rods 179 and180 are located in the same horizontal plane, in the manner depicted inFIG. 3, but in order to more clearly illustrate the construction, thetwo rods have been vertically displaced in FIG. 7 so that both rods andtheir relationship relative to each other may be clearly seen.

The rod 179 is slidably disposed within the bore formed in the feedslide 98 and extends through the feed slide and beyond its rearmostsurface where a nut 181 is thread-ed onto its rear end. The nut 181serves to retain a washer 182 on the rod to provide a bearing surfacefor one end of a compression spring 183 with the forward end of thespring 183 bearing against the surface of the feed slide 98 as clearlyshown in FIGS. 2 and 3. The spring 183 therefore serves to urge the rod179 in a rearward direction to force its end into engagement with thesurface of the back plate 150 and operates to retain the end of the rod179 in engagement with the surface of the back plate 150 during theinitial forward movement of the slides 98 and 142 so that the firstportion of the combined forward movement of the two slides is relativeto the rod 179 for reasons to be subsequently described.

The rod 180 is likewise slidably supported within a bore formed in thefeed slide 98 but its rear end is attached to the positioning slide 142by means of a pin 184. The rod 180 will therefore always move with thepositioning slide 142.

The rods 179 and 180 serve as links for coupling the inner quill 81 andthe outer quill 83 respectively to the slides 98 and 142 respectively,and are coupled to the quills by means of rollers 189 and 190respectively. The roller 189 is adapted to be received within a slot 191formed in the forward portion of the rod 179 as best shown in FIG. 7while the roller 190 is adapted to be received within a slot 192 formedin the forward portion of the rod 180.

The roller 189 is rotatably supported by a depending bracket 193 that isattached to the periphery of the inner quill 81 by suitable screws. As aresult, when the roller 189 is disposed within the slot 191, the innerquill 81 is coupled to the rod 179 for movement therewith. In likemanner, the roller 190 is rotatably supported by a depending bracket 194that is secured to the outer quill 83. The outer quill 83 is thereforecoupled to the rod 180 when its associated roller 190 is disposed withinthe slot 192 of the rod 180. It is therefore apparent that axialmovement of the rods 179 and 180 will effect a like movement of theinner quill 81 and the outer quill 83 respectively. Each of the severalinner and outer quills 81 and 83 that are located within the bores 26are provided with the rollers 189 and 190 for engagement with the slots191 and 192 of the rods 179 and 180. The rollers enter the slots 191 and192 when the drum 25 is indexed and moves a drilling or counterboringspindle 80 into operating position to couple the operative spindle withthe rods 179 and 180 and thereby with the slides 98 and 142. Indexing ofthe drum 25 cannot take place until the slides 98 and 142, and thereforethe rods 179 and 180 and the quills 81 and 83 are in their fullyretracted position.

When the quills 81 and 83 are in their fully retracted position asillustrated in FIG. 3, the rollers 189 and 190 are in alignment with anannular track generally identified by the reference numeral 201 andillustrated in FIGS. 2, and 6. The track 201 presents an annular channel202 for receiving the rollers 189 and 190 when they are moved out oftheir operative position by rotation of the drum 25. The track 201 ismounted on the saddle so that it is fixed relative to the spindles, andwhen the rollers 189 and 190 are disposed within the channel 202, thelatter serves to prevent lateral movement of the rollers and therebyretains the quills and their associated spindles in the fully retractedposition. In order to permit the axial movement of a spindle at theoperating station, a front wall of the channel 202 is interrupted toform an opening 203 shown in FIG. 5 and which coincides with theoperating position of the spindles. The opening 203 provides clearancefor the forward movement of the two rollers 189 and 190 which areassociated with a spindle which has been located by the drum at theoperating station.

As shown in FIG. 6, a back wall 205 of the channel 202 is provided withan opening 206 opposite the opening 203 to provide clearance to the rearof the spindle for the operation of the clutch 101 and the rods 179 and180 as well as for the upper portion of the feed slide 98 and thetransmission 96. An access opening 207 is also provided in the back wall205 displaced from the opening 203 for the purpose of withdrawing andreplacing the spindles and their associated quills from the bores 26 ofthe drum 25. The access opening 297 is closed during operation of themachine by a cover plate 212 that is secured to the track 201 by screws213. When replacement of a spindle in one of the bores 26 is required,the drum 25 is indexed until the spindle to be replaced is in alignmentwith the opening 207. With the cover plate 212 removed, the spindle andits associated quills may then be withdrawn from the bore 26 through theopening 207.

When the indexing of the drum 25 moves one of the spindles into theoperating station, its associated rollers 189 and 199 move into theslots 191 and 192 to couple the inner and outer quills 81 and 83 to therods 179 and 188 respectively. The hydraulic motor 147 is then actuatedto effect a positioning movement of the feed slide 98 and positioningslide 142 simultaneously, and since the rod 180 is connected to thepositioning slide 142 by means of the pin 184 it will move with theslide and thereby will cause a like positioning movement of the outerquill 83 by reason of its connections therewith through the placement ofthe roller 190 in the slot 192.

However, since the rod 179 is slidably supported by the feed slide 98and is retained in its rearmo-st position by the action of the spring'183, the rod 179 will not move with the initial movement of the twoslides but will remain stationary, and since the inner quill 81 iscoupled to the rod 179 by means of the roller 189, it too will remainstationary. Because the transmission 96 is mounted on the feed slide 98,its associated clutch element 103 will move with the feed slide towardthe clutch element 102 until the clutch elements 102 and 103 are fullyengaged to form a driving connection from the hydraulic motor to thespindle 80.

During this initial movement of the two slides, and until the clutchelements 102 and 103 are fully engaged, the limit switch 17 0 will beactuated by the dog 167 to insure that the hydraulic motor 147 isoperated at creep speed. It is not until the clutch elements 102 and 183are fully engaged that the limit switch is released by the dog 167 topermit further movement at a rapid rate if desired. However, while thelimit switch 17 0 is actuated by the dog 167, the electrical controlcircuit is so conditioned, as will be subsequently described, that arapid rate of movement of the slides 98 and 142 cannot occur.

As a precaution, to prevent further operation of the machine if by somereason the clutch elements 102 and 103 do not move into completeengagement, a limit switch 208 is fixed to the feed slide 98 andconnected in the electrical control circuit to prevent further operationof the machine if it is not actuated by engagement of the clutchelements 102 and 103. The limit switch 208 is actuated by moving aspring urged rod 209 to the right as viewed in FIG. 3, against thepressure of a spring 210. The rod 209 is normally urged to its extremeleftward position by the spring 219 and when the clutch elements 102 and103 become engaged, the bracket 193 abuts the left end of the rod 209and forces it rightwardly against the pressure of the spring 210 to movean enlarged portion 211 into engagement with the plunger of the limitswitch 208 to actuate the limit switch and indicate that properengagement of the clutch elements 102 and 103 has occurred so thatoperation of the machine can continue.

After the clutch elements 102 and 103 are fully engaged, it is no longernecessary for the inner quill 81 to remain stationary and it is desiredto then effect its forward movement. The front surface of the feed slide98 will then contact the roller 189 so that further forward movement ofthe feed slide 98 will cause a like movement of the roller 189 andthereby effect a corresponding movement of the inner quill 81 so that itwill then move together with the outer quill 83. Therefore, after thefront surface of the feed slide 98 contacts the roller 189, the combinedcross positioning movement of the feed slide 98 and the positioningslide 142 will produce a corresponding combined forward positioningmovement of the inner quill 81 and the outer quill 83.

During a drilling operation there may be a tendency for the drill topull the inner quill 81 forwardly relative to the feed slide 98 but thismay be avoided by positively coupling the inner quill 81 to the feedslide 98 after the clutch elements 102 and 103 are engaged and after thefront surface of the feed slide 98 is in engagement with the roller 189.To this end, the rod 179 which is associated with the inner quill 81 iscoupled to the feed slide 98 by means of a vertical plunger 215 that isslidably retained within a vertical bore 216 formed in the feed slide 98as clearly shown in FIGS. 2 and 3. A roller 217 is rotatably carried bythe plunger 215 so that its periphery extends above the upper extremityof the plunger while a similar roller 218 is likewise rotatably carriedby the plunger 215 so that its periphery extends beyond the lowerextremity of the plunger 215. A recess 219 is formed in the way 143 forreceiving the lower roller 218 of the plunger 215 when the feed slide 98and its associated positioning slide 142 are in the fully retractedposition. When the roller 218 is within the recess 219 the upper roller217 is disposed directly beneath the periphery of the rod 179.

When the roller 218 is located within the recess 219, the plunger 215 isin its depressed position so that the roller 217 is directly beneath andout of engagement with the rod 179. The purpose of the plunger 215 is tocouple the rod 179 to the feed slide 98 immediately after the frontsurface of the feed slide 98 contacts the roller 189 to effect apositive coupling of the quill 81 to the feed slide 98 so that theoperating drill cannot pull the inner quill 81 forwardly relative to thefeed slide 98.

To this end, the lower roller 218 moves with the feed slide 98 intocontact with an inclined wall 220 after the front surface of the feedslide 98 has contacted the roller 189. Continued movement of the feedslide 98 causesthe inclined wall 220 to move the roller 218 and itsassociated plunger 215 upwardly to move the upper roller 217 into arecess 221 formed in the rod 179. The lower roller 218 then moves out ofthe recess 219 and rolls along the way 143 to retain the upper roller217 within the recess 221 for the purpose of positively coupling the rod179 to the feed slide 98. Such coupling of the rod 179 to the feed slide98 is maintained until the feed slide 98 is again retracted to permitthe roller 218 to drop into the recess 219 which causes the plunger 215to drop to its depressed position.

If the clutch elements have become properly engaged the hydraulic motor147 will continue to operate to effect the simultaneous forward movementof the feed slide 98 and the positioning slide 142, and since the roller189 disposed within the slot 191 of the rod 179 is in contact with thefront surface of the feed slide 98, both rods 179 and 180 will move withthe slide to cause a like forward simultaneous movement of the innerquill 81 and the outer quill 83 for the purpose of properly positioningthe guide 89 with the spindle and its associated cutter for performing amachining operation. The outer quill 83 is provided to accommodate theguide 89 which is required for drilling operations. It will be notedthat during the positioning movement the outer quill 83 moves with theinner quill 81 so that the guide 89 will be positioned adjacent to theworkpiece and the feeding movement of the drill will then occur relativeto the guide 89 by actuating the inner quill 81 forwardly relative tothe outer quill 83. Forward movement of the slides 98 and 142 cancontinue at either a rapid rate or a creep rate until the dog 167act-uates the forward limit switch 171 to terminate operation of themotor 147 although such movement may be terminated sooner either man- 12ually or automatically as in response to a signal from a record.

If a counterboring operation is being performed, the feeding of thecounterboring tool into the workpiece is effected by the operation ofthe hydraulic motor 147 at a creep speed to cause the simultaneousforward movement of the feed slide 98 and the positioning slide 142 tomove both quills 81 and 83 forwardly and thereby produce a forwardmovement of the spindle and its associated counterboring cutter.However, if a drilling operation is being performed, the simultaneousmovement of the feed slide 98 and the positioning slide 142 functions toposition the guide 89 and the drill relative to the workpiece withoutactually feeding the drill into the workpiece. Such drill feedingmovement is produced by admitting hydraulic pressure into the right endof the cylinder 168 to force the piston 158 to the left as viewed inFIGS. 2 and 3. Such leftward movement of the piston 158 will serve toactuate the feed slide 98 relative to the positioning slide 142 in aforward direction, and since the roller 189 which is carried by theinner quill 81 has been engaged by the front surface of the feed slide98, the inner quill 81 will move forwardly with the feed slide 98relative to the outer quill 83 for feeding the drill 88 into theworkpiece. Such feeding movement of the feed slide 98 may continue untilthe piston 158 has reached its leftward limit of travel within thecylinder 168 although it may be terminated sooner either man ually orautomatically as in response to a suitable signal from a record when thedesired depth of drill feeding has been achieved. The feeding movementwill then have been completed and the drill 88 may be withdrawn from theworkpiece.

Withdrawal of the drill 88 from the workpiece is pro duced by reversingthe flow of hydraulic pressure into the cylinder 160, to cause arightward movement of the piston 158 and thereby effect a like movementof the feed slide 98 toward the positioning slide 142. The piston 158will be moved to its extreme rightward location within the cylinder 168,and the hydraulic pressure on the left side of the piston 158 will bemaintained for the purpose of coupling the feed slide 98 to thepositioning slide 142 so that the two slides will then move as a unit inresponse to operation of the hydraulic motor 147.

When the piston 158 arrives at its rightward limit of movement withinthe cylinder 160 to fully retract the feed slide 98 toward thepositioning slide 142, a limit switch 225 will be actuated to indicatethat the retracting movement has been completed and condition theelectrical circuit for subsequent operation. The limit switch 225 iscarried by the feed slide 98 for movement therewith and is actuated byan enlarged portion 226 on a rod 227 that is likewise carried by thefeed slide 98. The rod 227 is urged to the right, as viewed in FIG. 3,by a spring 228 to force the enlarged portion 226 out of engagement withthe plunger of the limit switch 225. However, when the feed slide 98 isfully retracted, the right end of the rod 227 will abut the positioningslide 142 in the manner illustrated in FIG. 3, causing a leftwardmovement of the rod 227 against the force of the spring 228 to cause theenlarged portion 226 to engage the plunger of the limit switch 225 andforce it downwardly for actuating the switch.

Actuation of the limit switch 225 by the enlarged portion 226 indicatesthat the retraction of the feed slide 98 is completed. The hydraulicmotor 147 may then be operated in a reverse direction to cause a furtherretraction of the feed slide 98 simultaneously with the re traction ofthe positioning slide 142. Such retracting movement of the two slidesoperates to likewise retract the inner quill 81 and the outer quill 83until the rollers 189 and 198 are in alignment with the track 201 sothat subsequent indexing of the drum 25 may occur to position anotherspindle in the operating location. After the inner quill 81 is fullyretracted, the retracting move- 13 ment of the feed slide 98 and thepositioning slide 142 continues to fully retract the outer quill 83. Atthe same time the roller 218 of the plunger 215 enters the recess 219 todepress the plunger 215 for releasing it from the rod 179 and therebypermit further retraction of the feed slide 98 relative to the rod 179.

The continued retracting movement of the feed slide 98 with thepositioning slide 142 then serves to move the clutch element 103rearwardly and out of engagement with the clutch element 102 todisconnect the spindle 89 from its driving connection with the hydraulicmotor 95. Therefore, when the slides 98 and 142 arrive at their fullyretracted position, the quills 81 and 83 will likewise be fullyretracted so that their associated rollers 189 and 190 are in alignmentwith the track 281 and the clutch elements 102 and 103 will be fullydisengaged to permit an indexing movement of the drum 25 to bringanother spindle into operating position.

In order to indicate the distance of movement of the positioning slide142 relative to the saddle 20, a scale 235 is mounted along the loweredge of the positioning slide 142 to cooperate with a plate 236 that iscarried by the saddle to indicate the distance of movement of thepositioning slide 142 relative to the saddle 20. In like manner, a scale237 is mounted on the feed slide 98 to cooper-ate with a plate 238 thatis carried by the positioning slide 142 to indicate the distance ofmovement of the feed slide 98 relative to the positioning Slide 142. Inthe event that the machine is arranged for automatic operation under thecontrol of a record or other positioning mechanism, the scales 235 and237 may be replaced by magnetic scales or similar components thatcooperate with reading heads. The reading heads. would replace theplates 236 and 238 and operate with the magnetic scales to produceelectrical impulses or the like for each small increment of movement ofthe positioning slide 142 and the feed slide 98 for cooperating with asuitable electrical control circuit for regulating the operation of thetwo slides in well known manner.

The operation of the mechanism has been described in connection with adrilling or counterboring operation in which a spindle 80 is utilizedfor rotatably supporting the drilling or counterboring tool. Aspreviously mentioned, the particular exemplary embodiment illustrated inthe drawings is also adapted to be utilized for performin-g tappingoperations, and because of diilerence in a tapping operation from adrilling or counterbori-ng operation, the spindle and quill arrangementcarried within the bores 26 of the drum must be modified to accommodatethe operation of the tapping tool.

Such tapping spindle and quill arrangement is illustrated in FIG. 4 andcomprises a tapping spindle generally identified by the referencenumeral 245. The tapping spindle 245 is rotatably supported within asingle quill 246 that is slidably carried within one of the bores 26 ofthe drum 25. It is to be noted that the single quill 246 is employedwith a tapping spindle 245 and the roller 189 is carried by the singlequill 246, while the two quills 81 and 83 are required for operationwith a drilling and counterboring spindle 80. The tapping quill 246 isprovided with a key 247 that is secured to the periphery of the quill bysuitable screws 248 and is disposed within the slot 86 formed in thedrum 25 contiguous with the bore 26.

The tapping spindle 245 includes a conventional tool retaining chuck 258at its forward end for removably securing a tapping tool 251 to theforward end of the spindle. The opposite end of the spindle 245 isprovided with a splined portion 252 for engagement with a cooperatingspline formed in a drive sleeve 253. The sleeve 253 is rotatablysupported within the quill 246 by a pair of ball bearings 254 and theclutch element 182 is secured to the sleeve 253 rather than directly tothe spindle. The power from the hydraulic motor 95 is theerfore transmitted through the clutch 101 to the sleeve 253 which, turn, operates todrive the spindle 245 by reason of its 14 connection therewith throughthe splined portion 252 the spindle being axially movable relative tothe sleeve 253 without interrupting the drive connection by reason ofthe splined engagement therewith.

The spindle 245 is also rotatably carried within the quill 246 by a ballbearing 268 that is mounted for movement with the axial movement of thespindle. The inner race of the ball bearing 268 is disposed between aflange 261 and a collar 262 both of which are secured to the spindle.The outer race of the ball bearing 260 is disposed within an annularbracket 263 which is provided with a tongue 264 that is received withinan elongated keyway 265 which serves to prevent rotational movement ofthe bracket 263 while permitting it to move axially with the movement ofthe spindle 245. The axial movement of the bracket 263 and itsassociated ball bearing 268 with the spindle 245 is effected by reasonof the location of the inner hace of the ball bearing 260 between theflange 261 and collar 262.

In performing a tapping operation, the axial movement of the spindle 245for each revolution of the spindle must be accurately maintained inorder to conform to the thread that is being formed by the tapping tool251. Therefore, the spindle 245 is provided with a threaded portion 269that is in engagement with a nut 270. The feeding movement is eilectedby rotating the spindle 245 and its associated threaded portion 269relative to the nut 270 to produce a forward axial motion of the spindle245. The nut 278 is provided with a pair of tongues 271 that extend fromdiametrically opposite points on the periphcry of the nut into thekeyway 265 and :a keyway 272 to prevent rotation of the nut 270 whilepermitting it to move axially within the quill 246.

The tongues 271 bear against the ends of the keyways 265 and 272 and areyieldably retained in engagement with the ends of the keyways by aspring 273 which has one end bearing against the end of the nut 270 andits opposite end bearing against the face of a collar 274 that isthreadedly engaged within the bore of the quill 246 to compress thespring 273 suificiently for retaining the tongues 271 of the nut 270 inengagement with the ends of the keyways 265 and 272 with enough force toresist the normal foces developed during tapping operations. However, ifthe tapping tool should strike an obstruction, the axial force on thenut 270 will increase substantially to overcome the pressure of thespring 273 and move the nut 270 rearwardly within the quill 246.

The lower tongue 271 of the nut 270 is disposed adjacent to a springurged plunger 279 which is urged upwardly by its cooperating spring intothe keyway 265 adjacent to the normal operating position of the lowertongue 271 of the nut 27 8. If the tapping tool 251 strikes anobstruction to move the nut 270 rearwardly within the quill 246', thetongue 271 will move with the nut to engage the plunger 279 and depressit to produce a like downward movement of a spring urged plunger 280 foractuating a tapping safety switch 281 which is carried within a bracket282, and serves to prevent further forward feeding movement of thespindle 245 when actuated. The bracket 282 is secured to the feed slide98 to move with it and extends forwardly therefrom. In addition to thesafety switch 281, the bracket 282 carries a forward limit switch 283, areverse limit switch 284, and a spindle identification switch 285.

The plungers of the switches 28 1, 283, 284 and 285 are in axialalignment for actuation by the plunger 280, a spring urged plunger 286,a spring urged plunger 287 and a spring urged plunger 288 respectivelywhich are also mounted in the bracket 282. The plungers 280, 286, 287(and 288 are carried for sliding axial movement by the upper portion ofthe bracket 282 and are urged upwardly by their cooperating springs torelease their associated switches. The four plungers carried by thebracket 282 are disposed to be actuated downwardly against the force oftheir cooperating springs to actuate their associated switches by thedownward movement of similar spring urged plungers carried by thetapping quill 246.

Thus, the spring urged plunger 280 is depressed to actuate the safetyswitch 281 by the downward movement of the plunger 279 when the nut 270is moved rearwardly as previously described. A pair of similar axiallyslidable plungers 289 and 290 are spring urged upwardly so that theirupper ends extend into the keyway 265 of the quill 246 to be actuated bythe tongue 264 of the annular bracket 263. When the spindle 245 reachesits forward limit of movement, the tongue 264 contacts the upwardlyextending portion of the plunger 289 to move it downwardly against theforce of its cooperating spring to, in turn, depress the plunger 286 andthereby actuate the forward limit switch 283 for stopping furtherforward feeding movement of the spindle. During reverse rotation of thespindle 245 when retracting the tapping tool 251 from the workpiece, thetongue 264 of the bracket 263* moves within the keyway 265 until itengages the upper extremity of the spring urged plunger 290 and forcesthe plunger downwardly against the force of its cooperating spring tomove the cooperating spring urged plunger 2 87 downwardly and therebyactuate the reverse limit switch 284 for stopping further reverserotation of the spindle 245.

The spindle identification switch 285 is actuated by a fixed plunger291, that is fixedly carried by the key 247 of the quill 246, wheneverthe clutch elements 102 and .103 are engaged and a tapping spindle is inoperating position, to indicate in the electrical control circuit that atapping operation is to be performed and condition the electricalcontrol circuit accordingly.

In FIG. 4, the spring urged plungers 280, 286, 287 and 288 are shownslightly offset from the plungers 279, 289,

290 and 291 that are carried by the quill 246 because the clutchelements 102 and 103 are shown as being disengaged. However, as theslides 98 and 142 move forwardly, the bracket 282 moves with the slidesand when the clutch elements 102 and 103 become fully engaged, theplungers carried by the bracket 282 are in alignment wlth the plungerscarried by the quill 246 so that downward movement of the plungerscarried by the quill 246 w1ll produce a like downward movement of theirassociated plungers carried by the bracket 282 to actuate theircooperating limit switches.

The operation of the slides 98 and 142 when a tapping spindle is inoperating position is identical to the operation described in connectionwith a drilling and counterboring spindle 80, except that the feed slide98 is not moved forwardly relative to the positioning slide 142 by thepiston 158 as is done to feed a drill into the workpiece. Instead, thespindle 245 is rotated to effect the feeding movement by reason of theengagement of its threaded portion 269 with the nut 270. Thus, when theslides 98 and 142 have moved the clutch element 103 into full engagementwith the clutch element 102, the front surface of the feed slide 98engages the roller 189 which is supported by the quill 246 so thatfurther forward motion of the slides 98 and 142 causes a like forwardmovement of the quill 246 to bring the tapping tool 251 into operatingposition relative to the workpiece. The spindle 245 will then be rotatedto effect its feeding movement.

Since the quill 246 is moving with the feed slide 98 and the positioningslide 142 after the clutch elements 102 and 103 are engaged by a reasonof the engagement of the front surface of the feed slide 98 with theroller 189 the bracket 282 being carried by the feed slide 98 will movewith the quill 246 at the same rate and the plungers carried by thebracket 282 will therefore remain in alignment with the plungers carriedby the quill 246 during the tapping operation so that they may functionas described. The four limit switches 281, 283, 284 and 285 operateduring tapping operations only, and do not function during any portionof a drilling or counterboring operation.

The hydraulic circuit illustrated in FIG. 8 functions to supplyoperating pressure and control the operation of the machine. Hydraulicpressure for actuating the piston 108 to shift the transmission 96 intoany one of its three speed ranges is obtained from a low pressure pump301 that draws pressure from a reservoir 302 through a conduit 303 anddischarges the fluid intoa conduit 304 leading to a spindle motor creepvalve 305. v

The valve 305 includes a slidable plunger 310 which is normally urged tothe left as viewed in FIG. 8 by a spring 311. With the plunger 310 inits normal postion as established by the spring 311, the fiow ofhydraulic pressure from the conduit 304 is blocked by the plunger 310.Energization of a solenoid coil 312 functions to shift the plunger 310against the pressure of the spring 311 to bring a passage 313 inregistration with the conduit 304 and a conduit 314 that carries thepressure from the conduit 304 to a pair of branch lines 315 and 316. Thebranch line 316 includes a check valve 317 which permits the flow offluid through the conduit 316 to a conduit 318 for operating the spindledrive motor at a creep speed. The gears in the transmission 96 willtherefore be rotated .at a slow rate to facilitate the shifting of thegears by operation of the piston 108.

Exhaust fluid from the spindle motor 95 flows into a conduit 323 andthence to a branch line 324 through a flow control or throttle valve 325which may be adjusted to regulate the rate of operation of the spindlemotor 95 at creep speed. From the flow control valve 325 the exhaustfluid flows into a conduit 328 which is connected to a port in the valve305 that registers with a passage 326 when the plunger 310 is in itsrightward position. The passage 326 then communicates with a conduit 327that connects with a return line 330 which functions to carry exhaustfluid back to the reservoir 302.

A portion of the low pressure fluid in the conduit 314 thereforeoperates the spindle drive motor 95 at a creep speed while the remainingportion is directed through a range selector valve 335 to the cylinder109 to actuate the piston 108 for shifting the transmission 96 into oneof its three speed ranges. To this end, the branch line 315 carrying thelow pressure fluid from the conduit 314 is connected to the valve 335which may be adjusted for actuating the piston 108 into any one of itsthree operating positions. The valve 335 includes a slidable plunger 336which is normally centrally located by a pair of oppositely actingsprings 337 and 338 that are located within the bore of the valve 335and act on opposite ends of the plunger 336.

With the plunger 336 in its normal central position as illustrated inFIG. 8, the flow of low pressure fluid from the branch line 315 flowsthrough a passage 339 formed in the valve plunger 336 as well as througha communicating passage 340 which is likewise formed in the plunger 336but connects with the passage 339. The low pressure fluid thereforeflows through both passages 339 and 340 in the plunger 336 with thepressure from the passage 339 flowing into a conduit 341 and thepressure from the passage 340 flowing into a conduit 342. The conduit341 communicates with the passage 116 to direct the flow of fluidpressure to the left end of the cylinder 109 as viewed in FIG. 8 whilethe conduit 342 connects with the passage to carry the low pressurefluid to the right end of the cylinder 109. Since hydraulic pressure ofsubstantially equal value is directed into both ends of the cylinder109, the piston 108 will be centrally located Within the cylinder toshift the transmission 96 to its low speed range in the mannerpreviously described.

The plunger 336 of the valve 335 may be shifted in either direction byenergizing either one of a pair of solenoid coils 343 and 344. When thesolenoid coil 343 is energized, the plunger 336 will shift to the rightto move a pair of parallel passages 34-5 and 346 into operating positionin registration with the conduits 341 and 342. When the passages 345 and346 are thus located, the hydraulic pressure from the branch line 31will flow through the passage 346 into the conduit 341 to the left endof the cylinder 109 to move the piston 108 to its rightward positionwithin the cylinder 109 for shifting the transmission 96 to its mediumspeed range. The exhaust fluid from the cylinder 109 will fiow throughthe passage 115 to the conduit 342 and thence through the passage 345 ofthe valve 355 into the return line 330 which carries the fluid back tothe reservoir 302.

Energization of the solenoid 344, on the other hand, will shift theplunger 336 to the left as viewed in FIG. 8 to bring a pair of passages352 and 353 into operating position to register with the conduits 341and342. When the valve plunger 336 is thus moved to its leftward position,the flow of hydraulic pressure from the branch line 315 will flow intothe passage 353 and into the conduit 342 which carries the pressure tothe right end of the cylinder 109 to actuate the piston 108 in aleftward direction to the left end of the cylinder 109. This movement ofthe piston 108 will shift the transmission 96 into its high speed rangeof operation as previously described. The exhaust fluid from thecylinder 189 will flow into the passage 116 and the conduit 341 andthence into the passage 352 formed in the plunger 336 which directs theexhaust fluid into the return line 330 for carrying it back to thereservoir 302.

It is therefore apparent that the range selecter valve 335 serves tocontrol the flow of fluid to cylinder 109 so that the transmission 96may be shifted into any one of the three speed ranges. Furthermore, thehydraulic circuit is so arranged that the shifting of the transmissioncannot occure until the transmission gears are slowly rotated at a creepspeed by the spindle drive motor 95 by virtue of the fact that thehydraulic pressure for shifting the piston 108 flows through the spindlemotor creep valve 305 which will not admit the flow of hydraulicpressure to the range selector valve 335 until the pressure is likewisedirected to the spindle drive motor 95 for actuating it at a creepspeed. The rate of movement of the piston 108 may be regulated byadjusting a flow control valve 354 that is connected in the branch line315 so that the flow of operating pressure to the valve 335 may beregulated for adjusting the rate of movement of the piston 108.

The pressure for actuating the spindle drive motor 95 at a normaloperating rate for rotating the tool carrying spindles is derived from ahigh pressure pump 360 under the control of a spindle motor directionalvalve 361. The pump 360 draws the fluid from the reservoir 302 through aconduit 362 and then discharge it into a conduit 363 that carries thepressure to the valve 361.

The valve 361 is provided with a slidable plunger 365 that is normallycentrally located within the bore of the valve 361 by a pair of springs366 and 367 that are located within the bore of the valve 361 to exert apressure on each end of the plunger 365. The central portion of theplunger 365 is provided with a U-shaped pas sage 368 that registers withtwo ports in the valve 361 to place the pressure line 363 in directcommunication with an exhaust line 369 which is connected to the returnline 330 to return the fluid to the reservoir 302. The passager 368therefore serves to by-pass the hydraulic motor 95 and circulates thehydraulic pressure from the pump 360 directly back to the reservoir 302.However, the motor 95 may be operated in either direction by energizingeither one of a pair of solenoid coils 370 and 371 which function tomove the plunger 365 to the right or to the left respectively, as viewedin FIG. 8, to direct the fluid pressure to the hydraulic motor 95 foropreation in either direction.

When the solenoid coil 370 is energized, the plunger 365 is moved to theright within the bore of the valve 361 to bring two parallel passages375 and 376 that are formed in the plunger 365 into registration withthe pressure line 363 and exhiust line 369 respectively. The pressurefrom the line 363 will then flow through the passage 375 into theconduit 318 which carries the pres- 18 sure to the hydraulic motor tooperate it in the reverse direction. The exhaust fluid is returned fromthe motor 95 through the conduit 323 and thence through the passage 376into the exhaust line 369 to flow into the return line 330 that carriesit back to the reservoir 302.

When the solenoid coil 371 is energized, the plunger 365 is moved to theleft to place a pair of passages 377 and 378 into communication with thepressure line 363 and the exhaust line 369 respectively. The pressurewill then flow from the pressure line 363 into the passage 377 andthence to the conduit 323 which carries the pressure to the motor 95 foroperating the motor in the forward direction. The exhaust fluid from themotor 95 is returned to the reservoir via the conduit 318, the passage378, the exhaust line 369 and the return line 330.

The exhaust line 369 includes a check valve 379 which limits the flow offluid in the line to one direction. The exhaust fiuid in the line 369flows through a flow control or throttle valve 380 which may be adjustedfor regulating the flow of fluid through the exhaust line 369 andthereby control the rate of operation of the motor 95 at operatingspeed. A pressure switch 381 is likewise connected to be actuated bypressure in the exhaustline 369 to serve as a protection for themachine, the pressure switch being electrically connected in theelectrical control circuit to stop the forward motion of the feed andpositioning sides 98 and 142 during a drilling and counterboringoperation while during a tapping operation the direction of rotation ofthe spindle is reversed to retract it from the workpiece, the pressureswitch 381 being actuated by an excessive drop of pressure in theexhaust line 369.

A relief valve 382 is connected to the lines 318 and 323 which lead tothe motor 95, the relief valve 382 serving to relieve the pressure inthe line in the event that an excessive pressure should build up in theline during the operation. Suitable check valves 383 and 384 beingconnected in the lines that lead to the relief valve 382 for directingthe flow of pressure to and from the valve for either direction ofoperation of the hydraulic motor 95.

The feeding movement of the feed slide 98 is actuated by high pressurefluid from the pump 360 directed to the cylinder through a feed controlvalve 390 which operates to control the flow of fluid to the cylinder160 for actuating the piston 158 in either direction. The feed controlvalve 390 includes a slidable plunger 391 disposed within the bore ofthe valve and normally urged to the left end of the bore by a spring392. When the valve plunger 391 is in its normal position as establishedby the spring 392 a pair of parallel passages 393 and 394 are incommunication with a pressure branch line 395 and anexhaust line 396respectively. The hydraulic pressure from the pump 360 will then flowinto a pressure line 397 to the pressure branch line 395 and thence tothe passage 393 in.the plunger 391. From the passage 393 the flow ofpressure continues through a conduit 398, a rapid traverse flow controlor throttle valve 399 and through a check valve 401, and thence into theconduit 162 to flow into the left end of the cylinder 160 for moving thepiston 158 to the right to retract the feed slide 98 from its forwardposition.

It will be observed that the spring 392 normally retains the valve 391in the position shown in FIG. 8 so that the pressure is maintained onthe left side of the piston 158 to couple the feed slide 98 to thepositioning slide 142 as previously described so that the feed slide 98will move with the positioning slide 142 upon actuation of the hydraulicmotor 147. Furthermore, since the flow of fluid to the left end of thecylinder 160 is always through the rapid traverse flow control valve399, the retraction of the feed slide 98 will always occur at a rapidrate of travel as distinguished from a feed rate of travel which isestablished by a separate feed flow control or throttle valve 405 thatmay be adjusted to regulate the rate of travel in the drill feedingmovement.

The feeding movement of the feed slide 98 is initiated )y energizing asolenoid coil 406 to shift the plunger 391 If the valve 390 to the rightof the position shown in FIG. l and thereby bring a pair of passages 406and 407 into .ommunication with the pressure branch line 395 and theeturn line 396 respectively. With the plunger 391 thus IOSltiOl'lCd bythe solenoid coil 406, the pressure from the ump 360 will flow throughthe pressure line 397, the iressure branch line 395, and thence throughthe passage L06 into the conduit 163 leading to the right side of theylinder 160. The exhaust fluid will return to the reseroir 302 throughthe conduit 162 and through the feed low control valve 405 because thecheck valve 401 will rrevent the flow of exhaust fluid directly into theline 88 but admits the flow of fluid in the opposite direction by-passthe feed flow control valve 405 to enable the eed slide 98 to beretracted at a rapid rate. However, luring the feeding movement, theexhaust fluid is comielled to flow through the feed flow control valveso that he feeding movement occurs at the desired feed rate. rom thefeed flow control valve 405 the exhaust fluid ontinues through the rapidtraverse flow control valve 99 and the conduit 398 into the passage 407and thence nto the exhaust line 396 connecting with a return line =08 toreturn to the reservoir 302.

The pressure in the line 397 from the high pressure ump 360 also servesto operate the cross positioning notor 147 for simultaneously actuatingthe feed slide 98 nd the positioning slide 142 in their path ofmovement. The operation of the motor 147 is under the control of a rosspositioning directional valve 415. The valve 415 3 provided with aslidable plunger 416 located within the lore of the valve and normallylocated in its central posiion by a pair of springs 417 and 418 that aredisposed on ither side of the plunger 416 to center' it Within the oreof the valve 415.

The plunger 416 is provided with a U-shaped pasage 419 that serves toby-pass the motor 147 when the lunger 416 is in its central or neutralposition as illusrated in FIG. 8. With the plunger 416 thus located, hepressure from the line 397 enters the valve 415 and .ows through theU-shaped passage 419 which directs into an exhaust conduit 420 thatconnects with the eturn line 408 to carry the fluid to the reservoir302. he exhaust conduit 420 has a creep flow control valve -21 connectedin it, the creep flow control valve 421 eing adjustable to regulate therate of operation of the 1otor 147 at creep speed. The exhaust conduit420 also lcludes a rapid traverse flow control valve 422 which isdjustable to regulate the speed of the motor 147 when he motor is beingoperated at a rapid traverse rate of peration.

The plunger 416 of the valve 415 may be moved to ither side of itsneutral position by energizing either ne of a pair of solenoid coils 427and 428 for operating 1e hydraulic motor 147 in either direction.Energiza- Ion of the coil 428 will function to shift the plunger '16 tothe left side of the bore of the valve 415 to ring a pair of parallelpassages 429 and 430 that are ormed in the plunger 416 intocommunication with the xhaust conduit 420 and the pressure line 397respective- I. With the passages 429 and 430 thus positioned With- 1 thevalve 415, the flow of pressure from the line 397 rill flow through thepassage 430 into a conduit 431 onnected to the motor 147 to operate themotor in the everse direction. The exhaust fluid from the motor 147 illflow into a conduit 432 to the passage 429 of the alve 415 and thenceinto the exhaust conduit 420 through 1e creep speed flow control valve421 and the return ne 408 to return to the reservoir 302.

Operation of the motor 147 in the forward direction achieved byenergizing the solenoid coil 427 to shift 1e plunger 416 to the right ofits central position. Such iovement of the plunger 416 will serve tobring a pair f passages 433 and 434 into registration with the presireline 397 and the exhaust conduit 420 respectively.

The flow of pressure from the line 397 will then proceed through thepassage 433 into the conduit 432 connected to the motor 147 to operatethe motor 147 in the forward direction. The exhaust fluid from the motor147 will flow into the conduit 431 to the passage 434 and thence throughthe exhaust conduit 420 through the creep speed flow control valve 421to the return line 408 to return to the reservoir 302.

The hydraulic motor 147 may be operated at a rapid rate of operation foractuating the feed slide 98 and the positioning slide 142 at a rapidrate by actuating a creep by-pass valve 435. The creep by-pass valve 435serves to direct the exhaust fluid from the motor 147 to by-pass thecreep speed flow control valve 421 and carry it through the rapidtraverse flow control valve 422 so that the rate of operation of themotor 147 is under the control of the rapid traverse flow control valve422 only.

The creep by-pass valve 435 is provided with a plunger 436 and has aport connected to a conduit 437 and a second port connected to a conduit438. A spring 439 is disposed within the right end of the bore of thevalve 435 to urge the plunger 436 to the-left and thereby block the flowof fluid from the conduit 437 to the conduit 438. When the valve is inthis condition, the exhaust fluid from the motor 147 will flow throughthe creep speed flow control valve 421 to limit the rate of operation ofthe motor to a creep speed.

However, a solenoid coil 440 may be energized to shift the plunger 436to the right end of the bore of the valve 435 and thereby bring apassage 441 formed in the plunger 436 into registration with the conduit437 and the conduit 438. The flow of exhaust fluid from the valve 415will then by-pass the conduit 420 and the creep speed flow control valve421 and flow through the conduit 437, the passage 441, the conduit 438and thence through the rapid traverse flow control valve 422 into thereturn line 408 so that the motor 147 will operate at a rapid rate asestablished by the rapid traverse flow control valve 422. It istherefore apparent that the hydraulic motor 147 may be operated ineither direction at either a creep speed or at a rapid rate.

A relief valve 445 is connected to the conduits 431 and 432 throughsuitable check valves 446 and 447 to relieve the pressure in the linesif it should build up excessively. With this arrangement, the reliefvalve 445 will protect the apparatus from excessive pressure in eitherthe conduit 431 or the conduit 432.

The electrical control circuit for controlling the operation of themachine is illustrated diagrammatically in FIG. 9. In the drawing therelay contact bars are shown in their normal position and are connectedto their cooperating relays by a broken line to indicate that they areactuated from their normal position upon energization of theirassociated relays.

Power for operating the machine is derived from a three phase sourcerepresented by the lines L L and L which are connected to energize apair of motors 456 and 457 through a master switch 458 and the normallyopen contacts of a relay 459. The control circuit illustrated in FIG. 9is energized by single phase current obtained from a transformer 460which has its primary coil connected to the lines L and L with itssecondary coil being connected to supply power to the control circuit.

The control circuit may be energized by closing a push button switch 461to complete a circuit from one side of the secondary coil of thetransformer 460 through a conductor 462 and a conductor 463 to a relay464. From the relay 464 the circuit continues through the closed startswitch 461 and a normally closed stop switch 465 and through a conductor466 to the opposite side of the secondary coil of the transformer 460 tocomplete the circuit. Energization of the relay 464 will serve to closeits normally open contact bars 467 and 468 and the closing of thecontact bar 467 will establish a holding circuit to maintainenergization of the relay 464 by by-passing the open start switch 461.The control circuit is de-energized by opening the normally closed stopswitch 465. Closing of the contact bar 468 serves to connect one side ofthe secondary coil of the transformer 460 to a line 470 while theopposite side of the secondary coil is connected to a line 471 through aconductor 472.

As previously mentioned, the machine may be operated manually orautomatically under the control of information obtained from a recordsuch as punched or magnetic tape. If the machine is to be controlledautomatically from the information on a record, a manual switch 473 isclosed to energize four automatic relays 475, 475A, 4758 and 475C.Energization of these four relays serves to condition the controlcircuit for automatic operation in response to information from a recordwhile if the operation is to be controlled manually by the operator, theswitch 473 is allowed to remain open.

The initial step in the operation is to select the speed range of thetransmission 96 by properly positioning the piston 108' within itscylinder 109 as previously described. This may be accomplishedautomatically by selective energization of a pair of relays 480 and 431in response to a suitable signal from a record, the relay 480 having anormally closed contact bar 482 while the relay 481 has a normally opencontact bar 483. By energizing one, both, or neither of the relays 480and 481, either one or neither of the solenoid coils 343 and 344 will beenergized to establish-either a low, medium or high speed range ofoperation of the transmission 96.

The speed range of the transmission 96 may also be established manuallyby manipulating a manual switch generally identified by the referencenumeral 490. The manual switch 490 includes three contact bars 491, 492and 493 which may be closed'individually or in combination bymanipulation of the switch to obtain the desired speed range. Thus, thelow speed range of operation may be obtained by manipulating the switchto close the contact bar 491 only. Closing of the contact bar 491 willcomplete a circuit'from the line 470 to the closed contact bar 491, anda normally closed contact bar 496 of the relay 475. Since the speedrange is being selected manually through the switch 490, the relay 475will not be energized so that its associated contact bar 496 will remainclosed. The circuit will then continue from the closed contact bar 496through a relay 498, completing the circuit through the line 471.

Energization of the relay 498 will serve to open its normally closedcontact bar 505 and close its normally open contact bars 506, 507 and508. With the electrical control circuit thus conditioned, neither thesolenoid coil 343 nor the solenoid coil 344 will be energized so thatthe plunger 336 of the range selector valve 335 will remain in itsneutral position directing hydraulic pressure to both sides of thepiston 108 to center the piston within the cylinder 109 for establishingthe low speed range of operation as previously described.

However, as previously described, in order to obtain a flow of pressureto the cylinder 109 through the valve 335 it is necessary to actuate thespindle motor creep valve 305 by energizing the solenoid 312.Energization of the relay 498 does operate to complete a circuit to thesolenoid coil 312 for actuating the valve 305. The current flows to thesolenoid coil 312 from the line 470 through the closed contact bar 508and a normally closed contact bar 516 of a relay 517. From the closedcontact bar 516 the flow of electrical current continues through thesolenoid coil 312 from whence it returns to its source through the line471. The solenoid coil 312 is therefore energized to actuate the valve305 and permit the flow of hydraulic pressure to the motor 95 fordriving the transmission at a creep speed as Well as to the cylinder 109through the 22 range selector valve 335 for shifting the transmission toestablish the selected low speed range.

When the low speed range is established, the plunger of the limit switch136 will drop into the notch 132 of the piston 108 as previouslydescribed to close the limit switch 136 and thereby indicate that theselected speed range has been established. Closing of the switch 136serves to complete a circuit from the line 470 to a normally closedcontact bar 520 of a relay 521. From the contact bar 520 the fiow ofcurrent continues through the closed contact bar 507 and the closedswitch 136 and thence to the relay 517. From the relay 517 the currentreturns to its source through the line 471. Completion of this circuitserves to energize the relay 517 and thereby open its normally closedcontact bar 516. Opening of the contact bar 516 breaks the circuit tothe solenoid coil 312 to cause the spindle motor creep valve 305 toreturn to its normal position and terminate the flow of hydraulic fluidto the cylinder 109 since the selected low speed range of operation ofthe transmission 96 has been established.

In similar manner, the medium speed range of operation of thetransmission 96 may beestablished by manipulating the manual switch 490to close its contact bar 493. The closing of the contact bar 493 willserve to energize the relay 521 by completing a circuit from the line470 through the closed contact bar 493, a normally closed contact bar430 of the relay 475, and the relay 521, the flow of current continuingfrom the relay 521 to return to its source through the line 471.Energization of the relay 521 will cause the opening of its normallyclosed contact bar 520 and the closing of its normally open contact bars533 and 534.

Closing of the contact bar 533 will complete a circuit to energize themedium speed range solenoid coil 343, the circuit originating from theline 470 and continuing through the closed contact bar 533, a normallyclosed contact bar 505 of the relay 498 to the solenoid coil 343 withthe current returning to its source from the coil 343 through the line471. Energization of the coil 343 will serve to shift the plunger 336 ofthe valve 335 so that the valve will direct fluid pressure to the leftend of the cylinder 109 for moving the piston 108 to the right end ofthe cylinder to establish the medium speed range of operation of thetransmission 96.

However, as previously described, in order to obtain a fio-w ofhydraulic pressure to the valve 335 for shifting the piston 100 it isnecessary that the spindle motor creep speed valve 305 be actuated tooperate the spindle motor at a creep speed and admit hydraulic pressureto the range selector valve 335. The valve 305 is actuated by energizingthe solenoid coil 312 and since the relay 521 was energized with theclosing of the contact 493, its contact bar 534 will close to complete acircuit for energizing the solenoid coil 312. The current for energizingthe solenoid coil 312 flows from the line 470 through the closed contactbar 534 to the normally closed contact bar 516. From the contact bar 516the flow of electrical current continues through the solenoid coil 312and returns to its source through the line 471. Upon energization of thecoil 312 hydraulic fluid will be admitted to the cylinder 109 forshifting the transmission 96 to its medium speed range of operation.

When the selected medium speed range is obtained, the plunger of theswitch 134 will drop into the notch 132 formed on the piston 108 toindicate that the speed range has been established. Closing of the limitswitch 134 completes a circuit to energize the relay 517. Energizationof the relay 517 serves to open its normally closed contact 516 andthereby break the circuit to the solenoid coil 312 for terminating theflow of hydraulic pressure to the range selector valve 335 and thereforeto the cylinder 109 and further operation of the machine may proceed.

If it is desired to operate the transmission 96 in its high speed range,the manual switch 490 is manipulated to close the contact bars 492 and493. With both of these contact bars closed, the relay 498 and the relay521 are both energized. Energization of the relay 521 serves to closeits contact bar 533 and energization of the relay 498 functions to closeits contact bar 506 to complete a circuit to the high speed solenoidcoil 344. Thus, the current will flow from the line 470 through theclosed contact bar 533, and the closed contact bar 506. From the contactbar 506 the flow of current continues to the solenoid coil 344 andreturns to its source through the line 471. Energization of the solenoidcoil 344 serves to shift the valve plunger 336 to the left within thebore of the valve 335 to direct fluid pressure to the right end of thecylinder 109 for shifting the piston 108 to the left end of the cylinderto establish the high speed range of operation of the transmission 96.

When the high speed range of operation has thus been established, theplunger of the limit switch 135 will drop into the notch 132 formed onthe piston 108 to actuate the switch into its closed position indicatingthat the high speed range of spindle operation has been established. Theclosing of the switch 135 will complete a circuit for energizing therelay 517 causing this relay to open its contact bar 516 and break thecircuit tothe solenoid coil 312 to permit the spindle creep valve 305 toassume its normally closed position and terminate the flow of hydraulicfluid for actuating the piston 108.

It is thus apparent that by manipulating the switch 490 into one of itsthree positions, the'transmission 96 may be shifted to any one of itsthree speed ranges. This same shifting may be accomplished automaticallyfrom information received from recorded data which will serve toenergize the relays 480 and 481 in predetermined combinations tocomplete the electrical control circuits in the same manner as describedfor operation of the switch 490.

After the transmission 96 has been shifted to the selected speed range,the relay 517 will remain energized and operation of the machine cancommence. With the feed slide 98 and the positioning slide 142 in thefully retracted position, a forward positioning signal from the recordeddata will energize a relay 549 if the machine is set for automaticoperation. Energization of the relay 549 will close its normally opencontact bar 550 to complete a circuit for energizing the solenoid coil427 which functions to actuate the cross positioning directional valve415 to initiate operation of the motor 147 for positioning the feedslide 98 and the positioning slide 142 in a forward direction. If themachine is being operated manually, the relay 549 will not be energized,but forward positioning can be initiated manually by manipulating amanual switch 551 to close its contact bar 522 which will also serve tocomplete the circuit for energizing the solenoid 427.

The current for energizing the solenoid 427 flows from the line 470 intoa conductor 553 to the limit switch 170. Since the limit switch 170 isbeing initially actuated by the dog 167 to retain the motor 147 in creepspeed, the current will flow from the switch 170 into a conductor 554 tothe pressure switch 381. The pressure switch 381 is likewise actuated byreason of the fact that there is hydraulic pressure in the hydraulicexhaust conduit 369 so that the pressure switch will conduct the currentto a conductor 555 and thence to a conductor 556 and a conductor 557 tothe feed limit switch 225. The feed limit switch 225 is also actuated byreason of the fact that the feed slide 98 is in its fully retractedposition so that the current flows from the limit switch 225 into aconductor 558 and thence through a normally closed contact bar 559 of arelay 560A. From the contact bar 559 the flow of current continuesthrough a conductor 561 to a normally closed contact bar 562 of a relay563.

Under automatic operation the current will continue from the contact bar562 through the closed contact bar 550 of the relay 549. However, undermanual operation, the current will flow from the contact bar 562 to theclosed contact bar 522 of the manual switch 551.. From the contact bar522 the flow of current continues through a normally closed contact bar566 of the relay 47513. The current flows from the contact bar 566through a closed contact bar 568 of the relay 517, the Contact bar 568being closed by reason of the fact that the relay 517 remains energizedafter the speed range for the transmission 96 has been established. Fromthe contact bar 568 the flow of current continues through a normallyclosed contact bar 570 of a relay 571 and thence through the closedcross positioning limit switch 171 to the solenoid coil 427, the currentreturning to its source from the coil 427 through the line 471.

The initial forward movement of the feed slide 98 and the positioningslide 142 much occur at creep speed until the clutch elements 102 and103 are fully engaged. After the slides have moved sufiiciently toengage the clutch elements, the dog 167 will release the limit switch sothat its contact bar will engage a contact 580 connected to a conductor581. It is only when the limit switch 170 is thus released that thesolenoid coil 440 can be energized to actuate the creep by-pass valvefor operating the feed and positioning slides at a rapid rate. Thecircuit for energizing the coil 440 originates at the line 470 with thecurrent flowing through the conductor 553, the limit switch 170, theconductor 581 and a conductor 582 to a contact bar 583 of the manualswitch 551. When the manual switch 551 is manipulated to initiateforward movement of the feed and positioning slides, the contact bar 583will move upwardly to bridge its upper cooperating contacts so that thecurrent can flow through the contact bar 583 into a conductor 584.

If the machine is being operated manually, the rapid traverse rate ofoperation of the feed and positioning slides 98 and 142 is initiated byactuating a push button switch 585 to its closed position so that thecurrent will flow through the switch 585 to a normally closed contactbar 587 of the automatic relay 475C and thence to the solenoid coil 440,the current returning to its source from the coil 440 through the line471.

If the machine is being operated automatically from recorded data, asignal from the record will energize a relay 595 to close its normallyopen contact bar 596. Under these circumstances, the manual switch 585will not be closed but the current will flow from the conductor 582,through a normally closed contact bar 598 of a relay 599 and thence to acontact bar 602 of the relay 4750. Since the machine is set forautomatic operation, the relay 475C will be energized to close thecontact bar 602 which will carry the current to a conductor 603 andthence through the closed contact bar 596 of the relay 595 to thesolenoid coil 440, the current returning to its source through the line471. Thus, the solenoid coil 440 may be energized either automaticallyby energization of the automatic relay 595, or manually by closing thepush button switch 585, and in either case the creep by-pass valve 435will be actuated to cause the hydraulic pressure to by-pass the creepspeed flow control valve and produce the forward positioning of the feedand positioning slides 98 and 142 at a rapid rate.

Although the release of the limit switch 170 by the dog 167 will permitenergization of the solenoid coil 440 for positioning of the feed andpositioning slides at a rapid rate, all forward movement of the slideswill terminate after the limit switch 17 0 is released if the clutchelements 102 and 103 are not fully engaged to actuate the clutch limitswitch 208. The actuation of the clutch limit switch 208 upon theengagement of the clutch elements 102 and 103 will complete a circuitfor energizing a pair of relays 610 and 610A which, in actual practice,are a single relay but are shown as two relays in FIG. 9 for the purposeof clarifying the drawing.

Upon release of the creep limit switch 170 by the dog 167 and theenergization of the relay 610 upon closing of the clutch limit switch268 with the full engagement of the clutch elements 102 and 103, aspindle verification circuit is completed to condition the electricalcontrol circuit for the particular type of machining operation that hasto be performed. If the machine is under manual control, a manual switch611 must be actuated from the neutral position shown in FIG. 9 to setthe circuit for a tapping operation or for a drilling and counterboringoperation. The manual switch 611 is provided with two contact bars 612and 613 both of which are shown open in FIG. 9 inasmuch as the switch isdepicted as being. in its neutral position. If a tapping operation is tobe performed, the switch 611 is manipulated to close the contact bar 612while if a drilling or counterboring operation is to be performed, theswitch 611 is manipulated in the opposite direction to close the contactbar 613. When the machine is being operated automatically from recordeddata the switch 611 is not manipulated and is allowed to remain in itsneutral position as illustrated in FIG. 9.

The quill verification circuit originates in the line 470 with thecurrent flowing through the conductor 553, the contact bar of the switch170 into the conductor 581 and thence to a closed contact bar 614 of therelay 610, the contact bar 614 being closed by virtue of the fact thatthe relay has been energized with the closing of the clutch limit switch208. The flow of current continues from the closed contact bar 614 tothe spindle identification switch 285.

The switch 285 is illustrated in FIG. 9 in its normal position with itscontact bar engaging a contact 616 to indicate that a drilling orcounterboring operation is to be performed. However, as previouslydescribed, if a tapping spindle is in the operating station, the plunger291 on the tapping spindle quill 246 will serve to actuate the switch285 when the clutch elements 102 and 103 are fully engaged. Actuation ofthe switch 285 will move its contact from the position illustrated inFIG. 9 to engage its cooperating contact 617 and thereby complete acircuit for energizing a tapping relay 560 to condition the electricalcontrol circuit for a tapping operation. If the machine is set forautomatic operation, a normally open contact bar 625 of the relay 475Cwill be closed by virtue of the fact that the relay 475C is energizedwhen the machine is set for automatic operation. The current forenergizing the tapping relay 560 will therefore flow from the contact617 of the switch 285 through the closed contact bar 625 into the relay560, the current returning to its source from the relay 560 through theline 471.

If the machine is set for manual operation, the contact bar 625 of therelay 475C will be open but a normally closed contact bar 629 of therelay 475C will remain closed and the current will flow from the contact617 of the switch 285 through the closed contact bar 629 and the closedcontact bar 612 of the manual switch 611 to energize the relay 560.Thus, the tapping relay 560 will be energized to condition the circuitfor a tapping operation if a tapping spindle is in operating positionand the clutch 101 is engaged, the tapping relay 56% being energized foreither manual or automatic operation of the machine.

The spindle identification switch 285 will not be actuated if a drillingor counterboring spindle is in operating position and its contact barwill remain in the position shown in FIG. 9 in engagement with thecontact 616. Furthermore, if the machine is under manual operation, anda drilling or counterboring operation is to be performed, the manualswitch 611 will be manipulated in a direction to close its contact bar613 so that a drilling relay 635 will be energized. The current willthen flow from the contact 616 of the switch 285 to a normally closedcontact bar 636 of the relay 475C, the contact bar 636 remaining closedsince the relay 4750 is not energized for manual operation of themachine. From the closed contact bar 636 the flow of current willcontinue through the closed contact bar 613 of the manual switch 611into a conductor 637 and through a normally closed contact bar 638 ofthe relay 599' and thence tothe relay 635. From the relay 635 the flowof current continues to the line 471 to return to its source.Energization of the relay 635 will condition the electrical controlcircuit for manually performing either a drilling or counterboringoperation.

Although the relay 635 will be energized for manually performing eithera drilling or counterboring operation, it will not be energized forautomatically performing a counterboring operation but it will beenergized for automatically performing a drilling operation. With thespindle identification switch 285 in the position shown in FIG. 9 toindicate that a drilling or counterboring operation is to be performed,in automatic operation either one of two relays 645 or 646 will beenergized by a signal from the recorded data to energize either therelay 635 to condition the circuit for an automatic drilling operationor the relay 599 to condition the electrical control circuit for anautomatic counterboring operation. The relay 599 is not energized formanually performing a counterboring operation since the feed andpositioning movement required in counterboring will all be performed bymanually controlling the operation of the machine.

A normally open contact bar 647 of the relay 475C will be closed if themachine is set for automatic operation. Furthermore, if the recordeddata produces a signal calling for a drilling operation, the relay 645will be energized by such signal to close its contact bar 648. Thecurrent will then flow from the contact 616 of the switch 285 throughthe closed contact bar 647 and the contact bar 643 into the conductor637 and through the normally closed contact bar 638 of the relay 599 tothe relay 635 to energize it. From the relay 635 the current will returnto its source through the line 471.

If a counterboring operation is called for by the recorded data, therelay 645 will not be energized but the counterboring relay 646 will beenergized by the signal produced from the data to close its associatedcontact bar 649. Closing of the contact bar 649 will serve to by-passthe contact bar 648 of the relay 645 so that the current will flow fromthe closed contact bar 647 of the relay 475C into a conductor 650,through the closed contact bar 649 to the relay 599. From the relay 599the current returns to its source through a normally closed contact bar653 of the relay 635 to the line 471 to complete the circuit forenergizing the counterboring relay 599.

After the electrical control circuit has been conditioned byenergization of either the relay 560, the relay 599 or the relay 635 asdescribed, cross positioning of the feed and positioning slides 98 and142 may be continued. The cycle of operation will vary somewhat for eachtype of machining operation and it will be first assumed that acounterboring operation under automatic control is to be performed.

In the case of counterboring it is desired that the spindle motor beactuated before the forward positioning of the feed slide 98 and thepositioning slide 142 occurs. Since the counterboring operation is to beperformed automatically under the control of information on a record,the relay 599 will be energizedto close its normally open contact bar660. Closing of the contact bar 660 serves to complete the circuit forenergizing a relay 599A causing it to open its normally closed contactbar 661 and close a normally open contact bar 662. It is to beunderstood that normally the relay 599 and the relay 599A will becombined into a single unit with the several contact bars under thecontrol of a single 2? :lay. However, for the convenience ofillustration, two :parate relays have been shown in the drawings.

With the closing of the contact bar 662 upon energizaon of the relay599A, a circuit will be completed to nergize the solenoid coil 371 foractuating the spindle rotor directional valve 361 to actuate the spindledrive rotor 95 in a forward direction. The electrical current )1energizing the solenoid coil 371 flows from the line 70 into a conductor663 to a normally closed contact ar 664 of the relay 560A. From thecontact bar 664 ie flow of current continues to the closed contact bar62 and thence to the tapping spindle forward limit vitch 283. Since thelimit switch 283 is not actuated, its Jntact bar will be in engagementwith its cooperating )ntact 668 to permit the flow of current through itto re normally closed contact bar 669 of a relay 670. From le contactbar 669 the flow of current will continue to contact bar 672 of therelay 517 and since the relay 17 was energized when the speed range ofthe transmison 96 was establish, the normally open contact bar 72 willbe closed to permit the flow of current thereirough. From the contactbar 672 the current flows to normally open contact bar 674 of the relay475C. .gain, however, since the machine is set for automatic peration,the relay 475C will be energized to close its Jntact bar 674. From thecontact bar 674, the cur- :nt flows into a conductor 675 and through arelay 680 nd returns to its source through the line 471. Energiation ofthe relay 680 will cause it to close its normally pen contact bar 682 tocomplete the circuit to the soleoid coil 371 for operating the spindlemotor in a forard direction. At the same time that the relay 680 losesthe contact bar 682 it also opens a normally closed antact bar 683 tobreak the circuit to the solenoid coil 70 which serves to actuate thedirectional valve 361 for perating the spindle in a reverse direction.Thus, the alenoid coil 370 cannot be energized while the relay 80 isenergized for energizing the solenoid coil 371 for perating the spindlemotor in a forward direction.

With the spindle motor 95 operating to rotate the pindle in a forwarddirection for a counterboring operaon, the solenoid coil 427 may beenergized to actuate 1e valve 415 for operating the motor 147 toposition the :ed slide 98 and positioning slide 142 in a forwarddiection, such combined forward movement of the feed lide 98 and thepositioning slide 142 also serving as a :eding movement in the case of acounterboring operaon for feeding the counterboring tool into theworkiece. When the relay 680 was energized to initiate forard rotationof the spindle, it closed an associated ormally open contact bar 688 tocomplete a circuit for nergizing a relay 680A. Energization of the relay680A perates to close its normally open contact bar 639 which erves tocomplete a circuit for energizing the forward ositioning solenoid 427.

The circuit for energizing the solenoid coil 427 origiates with the line470 and continues through a con uctor 690 to the closed contact bar 689of the relay 80A. From the closed contact bar the current flows to hecontact bar 692 of the relay 610A. The normally pen contact bar 692 isclosed by virtue of the energiation of the relay 610A so that thecurrent continues arough the pressure switch 381 and thence through theonductor 555, the conductor 556 and the conductor 557 a the feed reverselimit switch 225. From the switch 25 the current continues through theconductor 558, he closed contact bar 559 of the relay 560A and theonductor 561 to the normally closed contact bar 562 of 1c relay 563.

Since the counterboring operation is being automatially controlled froma record, the relay 549 will be enerized to call for forward positioningmovement. The urrent will therefore flow from the closed contact bar 62through the closed contact bar 550 of the relay 549 'J a closed contactbar 593 of the relay 475B, the contact bar 593 being closed because therelay 4753 is energized inasmuch as automatic operation has beenestablished. From the contact bar 593 the current flows to the contactbar 568 of the relay 517, the contact bar 568 being closed since therelay 517 was energized when the spindle speed range was established.

From the contact bar 568 the current flows through the normally closedcontact bar 570 of the relay 571 and thence through the closed forwardpositioning limit switch 171. From the switch 171 the flow of currentcontinues to the solenoid coil 427, returning to its source through theline 471. In this manner, the forward positioning coil 427 is energizedto actuate the positioning directional control valve 415 for directinghydraulic pressure to the motor 147 for moving the feed and positioningslides in a forward direction. If it is desired to effect this movementof the feed and positioning slides at a rapid rate for a portion of themovement, this may be accomplished automatically by a signal from therecord that energizes the relay 595 to complete the circuit to thesolenoid coil 440 as previously described. In like manner, such rapidrate of movement may be effected manually by actuating the manual pushbutton switch 585 to likewise complete the electrical circuit to thesolenoid coil 440.

The forward feeding movement of the feed slide 98 and the positioningslide 142 will continue until the desired depth of counterboring hasbeen obtained. At this point, under automatic operation, the relay 549will be de-energized in response to a signal from the record and a relay697 will be energized by the recorded data to close its associatedcontact bar 698. The opening of the contact bar 550 by de-energiaztionof the relay 549 will serve to de-energize the forward positioningsolenoid coil 427, While the closing of the contact bar 698 uponenergization of the relay 697 functions to complete a circuit forenergizing the reverse positioning solenoid coil 428 for actuating thevalve 415 to direct hydraulic pressure to the motor 147 for reverseoperation of the motor to effect retraction of the feed slide 98 and thepositioning slide 142.

The current for energizing the reverse solenoid coil 428 flows from theconductor 561 into a conductor 699 to the closed cross positioningreverse limit switch 168. From the switch 168 the fiow of currentcontinues to a conductor 701 and a conductor 702 to the closed contactbar 698 of the automatic relay 697. From the closed contact bar 698 thecurrent continues to a closed contact bar 705 of the relay 610, thecontact bar 705 being closed by energization of the relay 610 when theclutch 101 is engaged. From the contact bar 705 the flow of currentcontinues through a contact bar 707 or" the relay 475B, the contact bar707 being closed by energization of the relay 475B when the machine isset for automatic operation. From the contact bar 707 the currentcontinues to the relay 571 and returns to its source through the line471.

Completion of this circuit serves to energize the relay 571 causing itto close its normally open contact bar 710 and open its normally closedcontact bar 570. The current will therefore flow from the contact bar767 into a conductor 711 and thence through the contact bar 710 throughthe reverse positioning solenoid coil 428 to return to its sourcethrough the line 471. The circuit is therefore completed automaticallyto energize the reverse positioning solenoid coil 428 to effect aretraction of the feed and positioning slides 98 and 142. Thetermination of the forward movement of the feed and positioning slidesand the initiation of the reverse movement may be effected manually bymanipulating the manual switch 551 to open its contact bar 522 and closeits contact bar 713. The circuit will then be closed in like manner toenergize the reverse positioning coil 428. It will be noted that whenthe relay 571 is energized for completing the circuit to the coil 428,its normally closed contact 570 is opened to insure that the circuit tothe forward positioning solenoid coil 427 is broken.

When the clutch elements 102 and 103 become disengaged by the retractionof the feed and positioning slides 98 and 142, the limit switch 208 willbe released to deenergize the relay 610. The contact bar 705 of therelay 610 would then open to break the circuit to the relay 571 forenergizing the solenoid coil 428 for retracting the feed and positioningslides. However, a normally closed contact bar 715 of the relay 610 willclose to again complete the circuit, the current flowing from the switch168 to the conductor 701 and a conductor 716 and thence through theclosed contact bar 715 to continue as previously described for retainingthe solenoid coil 428 in its energized condition. It will be noted,however, that the circuit for energizing the solenoid coil 423 includesthe normally closed cross positioning reverse limit switch 168.Therefore, when the feed and positioning slides arrive at their reverselimit of movement, the dog 167 will actuate the limit switch 168 tobreak the circuit and de-energize the solenoid coil 428 to thereby stopthe reverse movement of the feed and positioning slides 98 and 142 tocomplete the counterboring operation.

In the case of a drilling operation the cycle is slightly different andthe quill verification circuit will therefore operate to energize thedrilling relay 635 instead of the relay 599 which was energized when acounterboring operation was selected. Energization of the relay 635 willclose its normally open contact bar 721 to complete a circuit forenergizing an associated relay 635A. Energization of the relay 635A willoperate to close its two normally open contact bars 722 and 723. Thecross positioning of the feed slide 98 and positioning slide 142 toposition a drilling operation will occur in the same manner as occurredfor a counterboring operation except that during the positioningmovement, the spindle will not be rotating as it was during thecounterboring operation.

The electrical circuit for energizing the forward cross positioning coil427 is the same as existed for a counterboring operation except that thecircuit will not originate with the conductor 690 and the contact bar689 inasmuch as the contact bar 689 will remain open in view of the factthat the spindle motor 95 is not operating. However, the current willflow through a conductor 724 to the contact bar 661 which remains closedin view of the fact that the relay 599A is not energized for a drillingoperation. The current will then flow from the closed contact bar 661 tothe contact bar 692 and thence proceed through the same circuitpreviously described to energize the forward cross positioning coil 427for effecting a forward positioning movement of the feed slide 98 andthe positioning slide 142.

In automatic operation the solenoid coil 371 will be energized toinitiate rotation of the spindle after the de sired positioning of thedrilling tool has been obtained by energizing a relay 725 in response toa signal on the record to close a contact bar 726 associated with therelay 725. If the machine is being operated manually to complete thedrilling operation, the solenoid coil 371 is energized by manuallyclosing a push button switch 727.

In automatic operation the current for energizing coil 371 will flowfrom the line 470 into the conductor 663 and the closed contact bar 664to the closed contact bar 722 of the energized relay 635A. From thecontact bar 722 the flow of current will continue to a conductor 729 anda conductor 730 to the closed contact bar 726 of the automatic relay725. From the contact bar 726 the current will flow into the switch 283'to the closed contact bar 669 and thence through the closed contact bar672, the latter being closed by energization of the relay 517 when thetransmission speed range was established. From the contact bar 672 thecurrent continues to the closed contact bar 674 which was closed byenergization of the relay 475C when the machine was set for automaticoperation. From the contact bar 674 the"- fiow of current continues intothe conductor 675 and through the relay 680 to return to its sourcethrough the line 471. Energization of the relay 680 closes its contactbar 682 to complete the circuit to the coil 371 for actuating the valve361 to initiate forward rotation of the spindle motor 95.

In manual operation the contact bar 726 of the automatic relay 725 willnot be closed but will be by-passed by reason of the fact that a contactbar 731 of the relay 475A will remain closed inasmuch as the relay 475Awill not be energized since the machine is not set for automaticoperation. From the contact bar 731 the current will flow through theswitch 283 and will continue as previously described. In addition, therelay 475C will not be energized for manual operation and contact bar674 is by-passed by the push button switch 727, the current flowing intoa conductor 734 to the closed push button switch 727. From the switch727 the current continues through a manual spindle stop switch 736 tothe relay 680, returning to its source through the line 471.Energization of the relay 680 will close its contact bar 737 toestablish a holding circuit for maintaining the relay 630 energizedafter the push button switch 727 is released, the relay beingde-energized manually by actuating the manual stop switch 736.Energization of the relay 680 will, as previously described, also closeits contact bar 682 to energize the solenoid coil 371 to initiateforward rotation of the spindle motor 95.

In the case of a drilling operation, the forward cross positioning ofthe feed slide 98 and the positioning slide 142 may continue until thedrill guide 89 is properly positioned relative to a workpiece with thelimit of forward movement being established when cross positioningforward limit switch 171 is actuated by the dog 167. Actuation of thelimit switch 171 will open it and break the circuit to the solenoid coil427 to terminate further forward movement of the feed slide 98 andpositioning slide 142. Normally, however, such positioning movement willbe terminated before the limit switch is actuated by the dog 167, withthe circuit to the solenoid coil 427 being interrupted byde-energization of the relay 549 in response to a signal from therecord, or if the machine is being operated manually, the positioningmovement will be terminated by actuating the manual switch 551 tolikewise break the circuit to the solenoid coil 427. In either case, thedrill guide 89 will be properly located with respect to the workpiecewhen the cross positioning movement is stopped and the drilling.operation may then be performed.

The drill feeding movement is obtained by energizing the solenoid coil406 to actuate the feed control valve 390' to cause it to direct fluidpressure to the right end of the cylinder for moving the piston 158 tothe left as viewed in FIG. 3 and thereby effect a feeding movement ofthe feed slide 98 relative to the positioning slide 142. The circuit forenergizing the solenoid coil 406 is completed when a contact bar 740 isclosed by energization of the relay 635 when the drilling operation wasselected and by closing a contact bar 741 which was closed when therelay 680A is energized to initiate rotation of the spindle. The feedingmovement will therefore be initiated immediately after the spindlerotation begins.

The current for energizing the solenoid coil 406 for automatic operationwill flow from the line 470 into the conductor 724 to the closed contactbar 661 and the closed contact bar 692 which was closed when the relay610A was energized upon actuation of the clutch limit switch 208 whenthe clutch elements 102 and 103 were engaged. From the contact bar 692the current continues through the pressure switch 381 into the conductor555 and thence to the closed contact bar 741 of the relay 680A. From thecontact bar 741 the current

